This project aims to describe variation in life history phenotypes that significantly affect fitness, and to analyze empirically and theoretically the forces that maintain variationand shape life histories and life-span. We aim to work at several levels - analyzing longitudinal data, developing and applying retrospective and prospective evolutionary theory, making and testing theory for honey bee life histories. The specific objectives are: (1) To characterize observed life histories as trajectories in stage-age space using longitudinal data on a relatively primitive human population (Tsimane, in collaboration with the Kaplan- Gurven project in this program), a modern human population (Framingham), Soay sheep and red deer, and medflies. (2) To explain observed, and to predict future, ecological and evolutionary dynamics, variation and equilibrium in phenotypic distributions, and in their mapping to survival and fertility. (3) Analyze optimal life histories in stochastic environments, focusing primarily on a stage-age model that describes the link between caloric restriction and lifespan. Also as part of this aim, we also study mutation- selection equilibria in stochastic optimality models (applying new results from the Wachter project in this program). (4) Develop and apply stage-age and hierarchical demography to honey bees, using vitellogenin titers and castes as stages. We will use data from the Page project in this program to make and test predictions about stage-specific mortality in workers, and the effect of transfers on queen mortality and reproduction. (5) Develop and apply theory for life history evolution in the presence of social interactions. (6) Use microsimulation to study mutation-selection equilibria as they shape human mortality in early humans. These microsimulation models will inform the analyses in (5) above, and will involve substantial interaction with the Kaplan-Gurven project. The completion of our aims will lead to a new framework for the the dynamics of quantitative traits, and of life history evolution, for stage-age-structured populations living in variable environments. RELEVANCE (See instructions): Health and mortality risk are widely recognized to depend on indivdual characteristics other than age. This research aims to understand the relationship between an individual's changing characteristics and health outcomes. We compare this relationship across many species of animals and plants,seeking general insights and constraints that will inform our understanding of the lives of individuals.